Scintillation detectors are generally used to detect high energy emissions such as high energy photons, electrons or alpha particles that are not easily detected by conventional photodetectors. A scintillator, or scintillation crystal, absorbs high energy emissions and converts the energy to a light pulse. The light may be converted to electrons (i.e., an electron current) with a photodetector such as a photodiode, charge coupled detector (CCD) or photomultiplier tube. Scintillation detectors may be used in various industries and applications including medical (e.g., to produce images of internal organs), geophysical (e.g., to measure radioactivity of the earth), inspection (e.g., non-destructive, non-invasive testing), research (e.g., to measure the energy of photons and particles), and health physics (e.g., to monitor radiation in the environment as it affects humans).
Scintillation detectors typically include either a single large crystal or a large number of small crystals arranged in an array. Many scanning instruments include scintillation detectors that comprise pixellated arrays of scintillation crystals. Arrays can consist of many scintillation pixels that can be arranged in rows and columns. Pixels may be positioned parallel to each other and may be retained in position with an adhesive such as an epoxy. The array may be positioned in an imaging device so that one end of the array (high energy end) receives excitatory energy and the opposed end (light emitting end) transmits resultant visible light to a photodetector. The depth of the array from the high energy end to the light emitting end is typically referred to as the x-ray depth. Light exiting the emitting exit end can be correlated to a specific scintillation event in a specific pixel, and this light can be used to construct a pattern of excitatory energy impacting the high energy end of the array.